Analytical devices and methods may be used to determine one or more analytes in samples of liquid. The liquid may comprise, for example, bodily fluids including, but not limited to, blood. The devices may be stationary, as in a laboratory instrument, or portable, as in a hand-held instrument.
Patient tests, such as those used in the care and treatment of diabetic patients, frequently employ disposable test elements for determining analytes in samples of bodily fluids, for example. Example disposable test elements include test strips. These test elements typically include a suitable analytical area that has been prepared on the test element. The determination of the analyte or analytes in the bodily fluid or some other sample of liquid is conducted by applying the sample of liquid to the analytical area of the test element where, normally, one or more test reactions occur. Following the application of the sample, the test element is evaluated using a testing or analytical instrument such as, for example, a hand-held instrument. The evaluation may involve, for example, an optical measurement, an electronic measurement, or both.
In some applications, optimal determination of the analyte in the liquid may require a surface within the analytical area to have hydrophilic properties that cause the liquid sample material to spread out easily. One method for forming a hydrophilic surface includes coating the analytical area with a hydrophilic material. Such a method has the drawbacks of a limited number of suitable materials and of tendencies for the hydrophilic material to influence the functionality of the test element. Because functional coatings must be chosen to satisfy very specific criteria, they are subject of extensive development activity that is time-consuming and expensive. Moreover, the application of the coating and the process control measures during production of the coatings also are prohibitively expensive. Though coatings can provide an effective hydrophilic surface within the analytical area of the test element, the coatings also limit the durability and the mechanical strength of the test element. Therefore, there remains an ongoing need for alternative methods and devices for forming hydrophilic surfaces on analytical areas of test elements.